Examples of color filters include color filters used in image output devices such as liquid crystal display devices and color filters used for image input devices such as solid-state image sensing devices. A typical example of the structure of the color filter used in liquid crystal display devices will be explained with reference to FIGS. 1A and 1B.
Generally, a color liquid crystal display device (101) has a structure in which, as shown in FIG. 1A, a color filter 1 is disposed opposite to an electrode substrate 2 such as a TFT substrate to form a clearance 3 of about 1 to 10 μm, a liquid crystal compound L is filled in the clearance 3 and the surroundings of these parts are sealed with a seal material 4. The color filter 1 has a structure in which a black matrix (hereinafter referred to as BM as the case may be) layer 6 formed with a predetermined pattern to shield the boundary portion between pixels, a pixel section 7 in which plural colors (usually, three primary colors, that is, R (red), G (green) and B (blue)) are arranged in the predetermined order, a protective film 8 and a transparent electrode film 9 are laminated in this order on a transparent substrate 5. An orientation film 10 is disposed on the inside surface sides of the color filter 1 and the electrode substrate 2 disposed opposite to the color filter 1. Also, a spacer is disposed in the clearance 3 to keep a constant and uniform cell gap between the color filter 1 and the electrode substrate 2. As the spacer, pearls 11 each having a fixed particle diameter are dispersed, or columnar spacers 12 having a height corresponding to the cell gap as shown in FIG. 1B are formed on the inside surface side of the color filter and in the region where it is overlapped on the position at which the black matrix layer 6 is formed. Then, the light transmittance of each of the pixels differently colored or the transmittance of the liquid crystal layer disposed behind the color filter is controlled to thereby obtain a color image.
Examples of the usual method of forming the pixels of the color filter in the form of a predetermined pattern include the dying method. In this dying method, first a water-soluble polymer material which is a dying material is formed on a glass substrate and then, patterned in a desired form by the photolithographic process. Then, the pattern obtained is dipped in a dying bath to obtain a colored pattern. These processes are repeated three times to form R, G and B pixels. Also, as other methods, there is a pigment dispersion method. In this method, a coating solution (pigment dispersion solution) containing a pigment which is a colorant and an alkali-soluble photocurable resin is applied to a substrate to form a photosensitive resin layer. This photosensitive resin layer is subjected to the photolithography process to form a predetermined pattern, thereby obtaining a monochromatic pattern. These processes are repeated three times to form R, G and B pixels. Further examples of the formation method include the electrodeposition method and the printing method in which a pigment is dispersed in a heatcurable resin to carrying out printing three times for forming R, G and B pixels and then, the resin is thermally cured.
However, any of these methods has the problem that it is necessary to repeat the same process three times to obtain three colors of R, G and B, thus leading to high cost and also, decreased yield because the same process is repeated.
As the method of producing a color filter which method is developed to solve these problems, a method is proposed in Patent Document 1 in which ink is sprayed on the surface of a substrate by the ink jet system to form a pixel.
When pixels are formed in the region enclosed in the black matrix layer on the transparent substrate by the ink jet method, pixels arranged at the opening part enclosed by the black matrix layer each have a part lower in thickness along the peripheral edge or its vicinity thereof and also, have the highest thickness on a position closer to the center side thereof than the part where the thickness is lower, or on the contrary, have the higher thickness along the peripheral edge or its vicinity thereof and also, have the lowest thickness on a position closer to the center side thereof than the part where the thickness is higher, or further have a concave-convex surface, resulting in the production of non-uniform pixels, depending on the affinity of the ink to the surface of the black matrix layer, the height of the black matrix layer and the amount of ink to be jetted.    Patent Document 1: Japanese Patent Application Laid-Open No. 59-75205